Rotameter



July 23, 1946. N. BREWER I ROTAMETER Filed April 27, 1943 5 Sheets-Sheetl July 23, 1946. N. BREWER 0 ROTAMETER Filed April 27, 1943 sSheets-Sheet 2' N. BREWER ROTAMETER Jul 23, 1946.

Filed April 27, 1945 a Sheets-Sheet s v Patented July 23, 1946 NathanielBrewer, Hatfield, Fischer & Porter Company,

Pa., assignor to Hatboro, Pa., a corporation of Pennsylvania ApplicationApril 27, 1943, Serial No. 484,710

11 Claims. 1

The present invention relates to flow-meters and it relates moreparticularly to flow-meters of the type commonly referred to asrotameters in which a generally vertical metering chamber havingvertically varying cross-sectional area is provided with a Verticallymovable float or sinker; the position of the float within the chamberdetermining the size of the orifice available for vertical flow of fluidthrough the chamber and being a measureof the rate-of-flow.

An object of the present invention is to provide a simple, inexpensiveand durable rotameter which can be installed in conventional pipe linesor the like, Another object of the present invention is to provide arotameter, the frame of which is made up of two identical andinterchangeable parts. Still another object of the present invention isto provide a rotameter in which the ,heads for connection to the ends ofthe metering chamber are adapted to be held in spaced relationship toeach other without the use of spacing bolts or columns. A further objectof the present invention is to provide a rotameter, the frame or housingof which consists of two identical and interchangeable castings whichcan quickly and easily be assembled and dis-assembled by means of simplebolts or the like. Another object of the present invention is to providea rotameter in which the metering tube is held between the heads of theframe solely by endwise compression and in which fluid-tight seals areprovided between the ends of the metering tube and the heads solely byend-wise gasketing. A further object of the present-invention is toprovide a rotameter in which the sealing pressure required formaintaining fluid-tight seals between the ends of the metering tube andthe heads is supplied by the fastening meansemployed to connect theparts of the rotameter frame to each other. Another object of thepresent invention is to provide a rotameter having inlet and outletopenings in the upright portions-of the frame. A further object of thepresent invention is to provide a rotameter in which the frame isprovided with conduits leading from the upper and lower head portionsthereof through the upright por-. tions and terminating in generallyhorizontally extending inlet and outlet openings disposed generallyintermediate the ends of the vertical metering tube. Still anotherobject of the present invention is to provide a rotameter which can beinstalled directly into a horizontal pipe line.

Other objects and advantages of the present lnvention are 1 apparent inthe following speciis to be understood that the variousinstrumentalities of which the invention consists can be variouslyarranged and organized and that the invention is not limited to theprecise arrangements and organizations of the instrumentalities asherein shown and described.

In the accompanying drawings in which like reference characters indicatelike parts throughout:

Figure 1 represents a perspective View of one embodiment ofthe presentinvention as it appears when disassembled.

Figure 2 represents a vertical cross-sectional view of the embodimentshown in Figure 1 in assembled position.

Figure 3 represents an end elevational view of the embodiment of Figure2.

Figure 4 represents a ment of Figure 2.

Figure 5 represents a view partly in vertical cross-section and partlyin perspective of the metering tube shown inFigur-es 1 and 2.

Figure 6 represents a horizontal cross-sectional view generally alongthe line 6-6 of Figure 2.

Figure 7 represents a horizontal cross-sectional view generally alongthe line l! of Figure 2.

Figure 8represents a horizontal cross-sectional view generally along theline 88 of Figure 2.

Figure 9 represents a view similar to that of Figure 5 but showing amodified form of metering tube in which the angle-cut flutes are given adownwardly-diminishing radial depth and in which the outside of the tubeis made conical.

Figure 10. represents a horizontal crosssectional view along the linel0l 0 of Figure 9.

'Figure 1 1 represents a horizontal crosssectional view generally alongthe line ll-l| of Figure 9. v

Figure 12' represents a horizontal crosssectional view generally alongthe line |2|2 of Figure Figure 13 represents a view similar to that ofFigure 5 but showing a further modified forni oi" fluted metering tubein which the flutes are rounded instead of being angler-cut as in theembodiments of Figures 5 and 9. 1

Figure 14 represents a horizontal crossplan view of the embodiviewgenerally along the erally along the line 1 Viewgenerally along the linea seating surface'44y 1 sectional view generally along the line 54-44 ofI Figure .13.

Figure represents a horizontal cross-sectional line |5-|5 of Figure 13.

Figure 16 represents a cross-sectional view similar to that of Figure 14but showing a tube hav- 1 ing tapered flutes which are generallyelliptical 1 in cross-section.

Figure 17 represents a view similar to that of having a conical ortapered inner bore. Figure 18 represents a cross-sectional view genFigure 5 but showing an unfluted metering tuba A similar pair of boltscan be inserted through the openings 45of the element 39b and can befastened within the screw-threaded sockets 43 of the lower element 39a.When the two pairs of bolts 46 are tightened, the end wall 42 of each ofthe housing elements 69 is held firmly against the seating surface ofthe other or the'housing elements to provide the assembled generallyrectangular rotameter frame or housing. 7

A relatively short thick-walled rotameter tube Figure 19 represents ahorizontalcross-sectional' Figure 20 representsa perspective view of astop pin alternative to that shown in Figures 1 and2. v

Figure 2d represents'a perspective view of an- 4 other modified form ofstop pin.

In the embodiment shown'in Figures 1 1308, I may provide a rotameterhaving a frame or housing formed of two symmetrical interchangeableelements which are designated generally by the'Treference character 36.The housing elements 39 are generally L'-shaped as shown particularly inFigure 1 and are adaptedto be. 'detachably connected to each other toform the generally rectangular rotameter'fra'me or housing. When theelements 3B are so connected, the'lower one element which is constitutesthe inlet housing designated more particularly as 39-a while the upperone constitutes the outlet housing element which is designated moreparticularly as til-b.

The housing elements 39 are adapted to support,and to providecommunicating conduits to, the ends of a'transpa'rent verticallydisposed metering tube 3| having a metering float 32 adapted for freeup-and-down movement therein."

Each of the housing elementstil is provided with a centrally-disposedopening t3extending from the inner face 34 of the bases-5 0i th L andforming a head portionfof the .rotameter frame or housing. Ascrew-threaded opening 39 extends in alignment with, and in continuationof, the opening 33 to the outer face 310i the'base 35. The opening 36 isadapted removably to receive a screw-threadedplug 38. f

A conduit 39 extends within the housing element' '30 from the centralopening 33 thereof through the upright portion or'arm 49' of the-L andterminates in an outwardly-extending screwthreaded opening 4| in theupright portion 49.

Theend wall 42 of the arm is'provided with a pair of inwardlyextendingscrew-threaded V sockets 43 whose function willbehereinaf-terde scribed;a 1.

The end of the base 35 is provided with a smooth slightly raisedinwardly-extending seatingsurface 44; a pair of drilledopenings 45extending through the base 35 from the outer face 31 thereof to the Theopenings '45 and the sockets 43 are symmetrically disposed on eitherside of-the central transverse plane of the housing member'sothat a pairof headed screw-threaded bolts 4ttcan be inserted through the openings'45-of the housing element 39-41, as indicated in Figure 1, and fastenedwithin the sockets-43- of the inverted elem'ent-Sil-b; the outer-ends-ofthe openings 45 being preferably enlarged to permit the. bolts 46 to becounter-sunk and to be. generally flush with the outer face 31 oithebase 35 whenfully screwed in.

9- 49 of Figure 17."

is'adapted to be held in an upright position between the housingelements 39.

One form of metering tube which'may be used with the rotam;

eter of my present invention, is the tube 3|,

5 which is thesubject 7 shown in Figures 1, 2 and of mycopendingapplication Serial No. 484,711, filed April 27, 1943, Patent No.2,377,861, granted June 12, 1945.

The metering tube 3| which is adapted to be held in upright positionbetween the housing elements 39 is a relatively short, thick-walledtransparent tube which is usually of glass (but which axis of the tubeso that maybe of transparentsynthetic plastic or other suitablematerial).

The metering tube 3| has a cylindrical outer surface 41 and is providedwith a generally cylindrical inner bore 48 within which the cylindricalmetering float 32 (or any other conventional type of metering float)fits with a relatively close annular clearance as shown, for example, inFigure'Z. A plurality (as are circumferentially disposed around theinner bore 4S and extend generally axially of the tube 3|. Eachextending plane side walls entially extending curved back wall '5 l.

of theflutes 49 'isformed byradially- 59 and a circumfer- The back walls5| are formed as segments of a cylindrical surface whose center ofcurvature lies at the same radial depth throughout theiraxial length.Theside'walls 5i] converge downwardly so that the flutes 49 have arelatively large circumferential dimensionat the top of the tube- 3|;(at which point the cylindrical inner bore 48 of the tube 3| is reducedto four small portions intermediate the flutes as shown in Figure 6) andso that the flutes terminate at the point of intersection of thesidewalls 59, somewhat abovethe lower end of the metering'tube 3 I.Slightly above the "lower ends of the flutes 49, the inside of thev tube3| would have the appearance shown in Figure '7 in which-the cylindricalbore 48 occupies'most ofth'eperiphery with the flutes 49 oocupying onlyvery small portions of the periphery.'-The lowermost portion 52" of thetube 3| (below the lower ends of the flutes 49) has a wholly cylindricalinner bore as shown in Figure 8. Y '4 a The tube 3| intermediate thelower is adapted to be positioned housing element 39-11 and the invertedupper housing element 39-b' with the inner bore ofthe' tubecommunicating with the central'0pening -33 in the housing elements.-

L'A' generall circular gasket-seat 53 is formed upon-the inner face 34of, the base 35 of the housing element surrounding the opening 33therein. A pair ofisimilar apertured compressible sealing 'gasketsj i,are disposed upon the gasket-seats 53 and are adapted to provide-afluid-tight seal intermediate the ends of the metering tube3| and thehousing elements 39-11 upper inverted housing I for example 4) of flutes49 the flutes 49 have the and 30b when end-wise pressure is exerted,upon the housing elements. 7

The dimensions of the several parts of the rotameter of the presentinvention are so propor tioned that, when the bolts 46 draw the endwalls 42 and the Seating surfaces 44 into contact with each other,end-wise pressure is exerted upon the gaskets 54 which is sufficient toprovide a fluidtight seal between the ends, of the tube 3| and thehousing elements but which is not great enough to cause breaking orstraining oi the relatively frangible metering tube. I r

The housing elements 30 are provided with removable stop pins 55 whichextend through generally horizontal apertures 56 acrossthe centralopenings 33 of the housing elementsyremovable screw-threaded plugs 51permitting side-Wise insertion and removal of the pins. When therotameter is assembled, the pins 55 extend horizontally just above andbelow the ends of the meter ingtube 3| and serve to limit theup-and-down movement-of the metering float 32. In thi way, the meteringfloat 32 is kept within the confines of the meterin tube 3| and isprevented from rising or falling into the apertures 33 of the housingelements 30.

In place of the separate pin 55 and plug 51, I may employ a stop pin 58,shown in Figure 20, in which the pin and threaded head are madeintegral.

Another form of stop pin is shown in Figure 21 in which a screw-threadedplug 53 adapted to be inserted within the opening 36 is provided with aninwardly extending stop pin portion 60 which limits the movement of thefloat.

The rotameter of the present invention is adapted to be quickl andeasily connected within either horizontal or vertical pipe lines.

Thus, for example, where it is desired to measure the'rate-of-flow of afluid moving in a horizontal pipe-line from left to right in Figure 2,the plugs 38 are inserted within the vertically extending screw-threadedopenings 36 of the housing elements 3||-a and 30b and the pipeline isconnected to the screw-threaded side openings 4| of the housing elements30; the side opening of the lower element 3|l-a forming the inlet andthe side opening of the upper inverted element 30-h forming the outletof the rotameter. The fluid entering from the pipe-line at the inletopening of the element 30-.0. passes through the conduit 39 and thecentral opening 33 of the housing element 30a and passes upwardly intothe cylindrical inner bore 48 of the metering tube 3| The upwardpressure of. the moving fluid lifts the metering float 32 upward withinthe tube beyond the lower ends of the flutes 49 whereupon the fluidenters the flutes, by-passing the float, and passes upwardly through thetube 3| beyond the float 32 into the central opening 33 and the conduit39 of the upper inverted housing element 30-b finally to leave therotameter through the side outlet opening of the element 30-!) and tocontinue its flow in the pipe-line.

The height of the float 32 within the metering tube 3| is a measure oftherate-of-flow of the fluid, the greater-the rate-of flow, the greaterthe height of the float within the tube. That is, when the float isstanding still at some point intermediate the ends of the tube, thepressure drop across the float of the rotameter is constant and is equalto the negative buoyancy of the float in the fluid. Upon any increase inthe rate-offlow, a momentary unbalance of pressure occurs (the pressurebeneath the float becoming greater 6 than the pressure above the float)whereupon the float is moved upward within the tube. But as the float ismoved upward, a greater by-pass' area is available to the fluid (due tothe fact that. the flutes become greater in cross-sectional area thefluid. The rotameter can be calibrated forv the particular fluid beingmetered so that the height of the float against the calibrations etchedor otherwise applied to the outside of the tube 3| Will be a directreading of the rate-of-flow of, the

fluid. Or, instead, the calibrations applied to the outside of the tubecan be an arbitrary scale, the

reading of which will givetherate-of-flow of any one of several fluidsby reference to suitable calibration and conversion tables.

Due to the fact that the flutes 49,,do not. extend to the bottom of thetube 3| sothat the float, at rest, is in the cylindrical lowermostportion 52 of the tube 3|, in which it has very slight clearance, eventhe slightest flow of fluid will be suflicient to raise the float 32appreciably within the tube 3|, so that the rotameter of the presentinvention is sensitive to very small flow rates. On the other hand, therotameter of the present invention has an unusually wide range:

due to the fact that the by-pass areapresented by the flutes increasesrelatively rapidly asthe float moves upward within the tube so that evenat relatively large flow-rates the float does not rise beyond the upperend of the metering tube 3| Where it is desired to measure therate-ofeflow of a'fluid moving in a horizontal pipe-line from right toleft in Figure 2, the rotameter is simply rotated around the imaginaryaxi of the meter ing tube horizontally so that the side inlet opening 4|of the lower metering element 30-a extends toward the rightto receivethe oncoming fluid from the pipe-line and so that the side out-,,

let opening 4| of the inverted housing element 30b extends toward theleft of the rotameter; the functioning of as described hereinabove.

Whereit is desired to measure the rate-of flow of a fluid movingupwardly within a vertical pipe-line, the plugs 38 are removed from thevertically-extending screw-threaded openings 36, and are inserted withinthe side openings 4| of the housing elements :30; the pipe-line beingcon- 36 as shown; in dotted lines in Figure 2. Whenthe rotameter is socon nected into the openings nected, the upwardly moving fluid will passthrough the opening 33 of the lower housing element 3||a and into themetering tube 3| to by-pass the float 32 through the flutes 49, finallyto leavethe opening 33 of the upper housing element 30-?) th ough theopening 36 thereof. j I

Therotameter of the present invention can also be "so installed a tochange the direction of flow of fluid in a pipe line. possible to changefrom by connecting the, horizontal pipe-line to the side inlet opening4| 'of the housing element 3||a and by connecting the vertical pipe-lineto the outlet opening 36 of the housing element 30b; the opening 36inthe housing element 30-a' and the opening 4| in the housing element 30-hbeing closed by the plugs 38. Similarly,

the rotameter being the same Thus, for example, it is" horizontal tovertical flow l atively expensive each rotameter has been orderedaccording to the particular requirements of the proposed instaL- use inmany places where 1 other hand, employing as it is possible to changefrom vertical to horizontal flow by connecting the vertical pipe-line tothe The housing elements30 can be readily and inexpensively formed assingle castings in which the necessary openings and conduits can beformed .by drilling or other conventional opera- 1 tions.

Since the housing elements are identical and fully interchangeable, itis necessary to manufacture and to stock only a single type of housingelement, which with the metering tube, gaskets and necessary bolts andplugs can easily be assembled and installed by any pipe-fitter or 1mechanic of average ability.

Rotameters, as heretofore used, have been reland made to order in thatlation. Rotameters, being precision instruments, have heretofore beeninstalled only by specially trained and skilled men and suchinstallation has required specialized and relatively expensive fittings,etc. Thus, for example, a rotameter, as heretofore used, may consist ofthe metering tube,

3 separate inlet and out1et.heads-or fittings, a

plurality of supporting and spacing bolts or col- 1 umns for the heads,7

the ends of the tube including packing and stufistufling boxes forenclosing ing glands, bolts, etc. Where the fluid to be metered waspassing through a horizontal pipeline, rotameters as heretofore knownrequired special piping arrangements since their inlet and outletopenings were at different levels.

As the result of these and other factors, rotameters, as heretoforeknown, have been sold only at prices which are too high to permit theirthe inexpensive determination of the flow-rate of a fluid is able. 7 g

The rotameter of my present invention, on the it does a single type ofinterchangeable housing element and eliminating the expensivestufiing-box, and greatly reducing the number of parts, as'well assimplifying the installation thereof, can be sold and installed at afraction of the cost of conventional rotameters. The advantages of therotameters as a flow-rate indicator are thus, for the first time, madeavailablein a large and varied field of industrial and homeuseinconnection with the termination of fluid flow-rate. V V

While so-called one-piece rotameters are known, the expression one-pieceis misdescriptive of these oconventional rotameters, since the latter,in reality,

on the other hand, has only two metal parts and two sealinglelements(the gaskets at the ends of the metering tube). i 1

In place of the metering tube 31 shown 7 Figures 1, 2 and 5, I mayemploy other types of.

fluted metering tubes such as, for example, those desir' inexpensivedeare composed of an integral metal frame (having upper'and lower headsand connecting columns), upper and lower separate shown in Figures 9 to12 and 13 to 15 of the drawings.

Thus, for example, I may employ the fluted tube 6! shown in Figures 9 to12. The tube 6| has a cylindrical inner bore 62 generally similar to theinner bore 48 of the tube 3!. However, the outer surface 63 of the tube6| is made conical with a relatively slight downward taper.

A plurality (as for example 4) of flutes 64 are circumferentiallydisposed about the cylindrical inner bore 62 of said tube 6| and extendgenerally axially of said tube. Each of the flutes 64 is formed by apair of plane radially-extending downwardly converging side walls 65 anda back wall 66 which is formed as a segment of a conical surface havingits axis of curvature at the axis of the tube and being downwardlytapered at an angle more or less approximately parallel to the angle oftaper of the outer conical surface 63.

Thus, the flutes 64 vary not only in circumferential dimension (as isthe case with the flutes 49 ofthe tube 3|) but also in radial depth; theflutes being large in circumferential and radial dimension near theirtops as shown in Figure 10 and being small in both radial andcircumferential dimension near their bottoms as shown in Figure 11. Theflutes 64 terminate somewhat above the lower end of the tube 6! so thatan unfluted cylindrical inner surface 61 is presented at the lowermostportion of the tube 6| Still another form of metering tube is the tube68 shown in Figures 13 to 16,. The tube 68 has a cylindrical inner bore69 and a cylindrical outer surface 16. A plurality (as for example 4) offlutes H are circumferentially disposed about the inner bore 69 andextend generally axially of the tube 68. Each of the flutes 1! (insteadof being angle-cut as are the flutes of the metering tubes 31 and 61) issmoothly curved and is formed. as a segment of a concavely conicalsurface having a downward taper. In this embodiment, the flutes llextend the entire axial dimension of the metering tube 68; the flutesbeing large and deep near the top of the tube as shown in Figure 14 andbeing smalland shallow near the bottom of the tube as shown in Figure15.

The rounded tapered flutes, instead of having the circularcross-sectionshown in Figures l3, l4 and 15, may be given any other smoothlycurvedcross-sectional configuration, as for example the ellipticalcross-section shown in Figlire 16.

Instead of a fluted metering tube, 1 may employ the metering tube 12shown in Figures 17,

' l8 and 19 which has a conical downwardly tapered inner bore 13 and acylindrical outer surface 14.

The metering tubes 3 I, 6 I, 66 and 1'2 have been described hereinaboveonly by Way of example and it is to be understood that the novelrotameter of my present invention may employ any metering tube whichpresents substantial end walls so as to permit end-wise gasketingbetween the tube and the housing elements. 7

The metering tubes employed with the rotameter of the present inventionmay be calibrated (by etching or otherwise) upon the outer'sur face, asshown in Figure 1 or upon the inner cylindrical bore, as shown in Figure9 or both as shown in Figure 13; the dual calibration shown in Figure 13being eflective to prevent refractive error which might otherwise resultfrom the thick wall of the metering tube if the float were viewed at anangle other thanthe horizontal. The present invention may be embodied ined claims rather than to the foregoing description to indicate the scopeof the invention.

Having thus described my invention, what I claim as new and desire, toprotect by Letters Patent is:

1. A rotameter comprising a vertical metering tube having a meteringfloat adapted for free up-and-down movement therein, a pair of identicaland interchangeable generally L-shaped elements constituting the endfittings as well as the frame for the metering tube, and means fordetachably securing said elements directly to each other in operativerelation to the ends of the metering tube, said frame having alignedhorizontal openings therein whereby said rotameter can be connecteddirectly within a horizontal pipe-line.

2. A rotameter comprising a vertical metering tube having a meteringfloat adapted for free upand-down movement therein, a pair of identicaland interchangeable generally L-shaped elements constituting the endfittings as Well as the frame for the metering tube, each of saidelements having a conduit leading from an opening on the inner sidethereof adapted for connection to one end of the metering tube andleading to an opening on the outer side thereof for connection to apipe-line, and means for detachably securing said elements directly toeach other and for simultaneously supporting said metering tubeintermediate said elements with the ends of the tube disposed influid-tight relationship to the inner openings of said elements.

3. A rotameter comprising a vertical metering tube having a meteringfloat adapted for free up-and-down movement therein, a pair of identical and interchangeable generally L-shaped juxtaposed elementsdetachably secured directly to eachother to form the frame for themetering tube and constituting the end fittings thereof, said elementshaving aligned horizontal openings and conduits formed therein, saidmeterin tube being supported intermediate said elements with the ends ofthe tube in fluid-tight sealing relationship to said conduits, saidconduits forming a continuous passageway from said metering tube to saidaligned openings.

4. A rotameter comprising a continuous frame formed by a pair ofidentical and interchangeable generally L-shaped juxtaposed elementsdetachably secured to each other, a vertical metering tube having ametering float therein and being supported intermediate said elementswith the opposite ends of the tube in fluid-tight sealing relationshipto connecting passageways formed in said elements, saidpassagewaysterminating in aligned horizontal outlets adapted forconnection to a pipe-line, and a horizontal pin removably disposedwithin each of said elements, said pins providing top and bottom stopsfor said metering float.

5. A rotameter comprising a continuous frame formed by a pair ofidentical and interchangeable generally L-shaped juxtaposed elementsdetachably secured to each other, a vertical metering tube having ametering float therein and being supported intermediate said elementswith the opposite ends of the tube in fluid-tight sealing relationshipto connecting passageways formed in said elements, said passagewaysterminating in aligned oppositely extending horizontal outlets adaptedfor connection to a pipe-line.

6, A rotameter comprisinga continuous frame formed by a pair ofidentical and interchangeable generally L-shaped juxtaposed elements de-'tachably secured to each other, a vertical metering tube having ametering float therein and being supported intermediate said elementswith the opposite ends of the tube in fluid-tight sealing relationshipto connecting passageways formed in said elements, said passagewaysleading to aligned oppositely extending horizontal outlets and also toaligned oppositely extending vertical outlets, said horizontal outletsand said vertical outlets being adapted for alternative connection to apipe-line.

7. A rotameter comprising a continuous frame formed by a pair ofidentical and interchangeable generally L-shaped juxtaposed elements,fastening means detachably connecting said juxtaposed elements andpulling said elements vertically together, a vertical metering tubedisposed intermediate said elements and supported at its ends thereby,apair of compressible annular sealing members disposed intermediate theends of the tube and the adjacent portions of said elements, saidsealing members being compressed upon fastening of said fastening meansto provide a fluid-tight seal intermediate said elements and the ends ofsaid tube, said elements havin conduits formed therein leading from theends of said tube and terminating in aligned oppositely extendinghorizontal outlets adapted for detachable connection in a pipe-line.

8. A rotameter comprising a frame formed of a pair of generally L-shapedhousing elements of metal having conduits formed therein, meansdetachably connecting said housing elements, a relatively thick-walledmetering tube having a freely-movable metering float therein and beingvertically disposed intermediate said housing elements, said framehaving aligned horizontal openings communicating with said metering tubethrough said conduits, and a pair of plane annular sealing membersdisposed intermediate said housing elements and the end Walls of saidmetering tube, said sealing members being axially compressed uponfastening of said connecting means to provide a fluid-tight end-wiseseal intermediate said metering tube and the conduits formed in saidhousing elements.

9. A rotameter adapted for connection directly into a horizontalpipe-line comprising a continuous frame formed by a pair of generallyL-shaped housing elements of metal having conduits formed therein, saidelements being detachably held in abutting relationship by connectingmeans, said housing elements having aligned oppositely extendinghorizontal openings commu nicating with said conduits and adapted forconnection to the pipe-line or the like, and a metering tube having afreely-movable metering float therein and being vertically heldintermediate said housing elements in fluid-tight sealing relationshipwith said conduits.

10. A rotameter comprising a continuous frame formed by a pair ofidentical and interchangeable generally L-shaped elements havingconduits therein, means detachably connecting said elements in abuttingrelationship with each other, a metering tube having a metering floattherein and being vertically disposed intermediate said frame elements,and a pair of annular compressible sealing members intermediate saidframe elements and the ends of said metering tube, said annularsealing'members being axially compressed upon fastening of saidconnecting means, to provide a fluid-tight seal between said meteringtube and said conduits.

11. Arotameter comprising a continuous frame 7 formed by'a pair ofidentical and interchangeable generally L-shaped castings havingconduitstherein, means detachably connecting said castings in abuttingrelationship with eachother, a metering tube having a metering floattherein and being vertically disposed intermediate said frame castings,said frame having aligned 'hori- 10 zontal openings thereincommunicating with said metering tube through said conduits, and apairof annularscompressible sealing members inter- NATHANIEL BREWER.

